Not yet developed; not yet having a finished shape. You use it for something that exists but has not grown into what it will become. It is common for thoughts and plans: an unformed idea is one you can feel but cannot explain yet, still cloudy in your head. It also works for people — an unformed personality, unformed opinions — meaning young and still changing, and this use is gentle rather than insulting; it says 'not finished' rather than 'bad'. Then there is a more physical use, closer to the plain meaning of the parts: unformed clay, unformed bones in a baby, something with no clear shape at all. Doctors and biology books use it that way. Take care with the feeling of the word. Unlike many un- words, it is not usually a criticism; it is closer to 'early', 'raw', 'still becoming'. Writers like it for exactly that, because 'unformed' admits that something real is there while being honest that it is not ready. It is a somewhat literary and thoughtful word — you meet it in books and serious articles more than in conversation, where people would just say 'not clear yet' or 'still working it out'.

尚未成形的、還沒定型的。指想法、性格、形狀都還在發展中，不是在批評，比較像「還沒長成、還在摸索」。